The present invention relates generally to a multi-ligator device, and associated accessory devices. More specifically, the present invention relates to a multi-ligator device that generates a signal when a ligation ring is released and to an ergonomic accessory kit for mounting the ligation rings onto the ligation head of the present invention.
The ligation of vessels is a commonly used medical procedure. It has long been common to treat lesions, such as hemorrhoids and esophageal varices by ligation. The object of ligation is to position an elastic cord, or ligation ring, around the lesion to stop circulation through the tissue and cause the tissue to die whereupon the body sloughs off the dead tissue. One instrument for facilitating the placement of a single ligating band or a set of bands is a ligator head that can be constructed using two rigid, concentric tubes. The inner tube slides with respect to the outer tube under the manipulation of a control unit that is located at the proximal end of the instrument. A flexible or rigid endoscope having internal passages forming a suction path and a light path interconnect the control unit and the ligator head. The ligator head can be loaded with a set of one or more elastic rings or ligating rings. When the ligator head is located proximate a lesion, a surgeon applies suction to draw tissue into the hollow passage at the distal end of the ligator head. The control unit can then be manipulated to retract the inner tube of the ligator head. This causes the larger diameter of the outer tube to engage the ligating ring and, as the inner tube of the ligator head is withdrawn, a ligation band slides off of the ligator head and elastically contracts around the targeted tissue.
Another type of ligator head that is used has an inner tube that moves axially with respect to an outer tube that is attached to the distal end of an instrument. For example, the outer tube can be attached axially onto the distal end of an endoscope. A control unit then manipulates the ligator head via a rotatable flexible shaft that maintains position on the inner tube so that it does not displace axially outwardly while the instrument is being positioned. Suction can be applied to draw tissue into the central aperture of the ligator head formed by the inner tube. Then, a surgeon manipulates the control unit to retract the inner tube axially past the distal end of the outer tube to force a ligation ring to detach from the ligator head and elastically cinch the targeted tissue.
In German utility model 297 09 170.0 a multi-ligator device for use with endoscopes is described, by which several ligation rings can be placed one after the other at different tissue locations. Advantageously, the inner cylinder of the ligator head onto which the ligation rings are loaded is pulled precisely backwards by a threaded spindle, so that the movement of the endoscope and the compression of the endoscope have no influence on the releasing of the rings.
Despite the advantageous mechanical decoupling contained in German utility model 297 09 170.0, there remains the disadvantage that upon the rotation of the threaded spindle the operator has no direct mechanical feedback corresponding to when a ligation ring is released. This problem did not exist in the older ligator systems that used a mechanically coupled system to control the ligator head. With the older systems, the operator could rely on tactile senses to determine when a ligation ring was released by sensing the vibration transmitted along a cord connecting the ligator head to the control unit.
The present invention overcomes the above drawback that occurs with control units that are mechanically decoupled. This is accomplished by generating a signal that corresponds to the detachment of a ligation ring from the ligator head. Thus, the present invention facilitates the use of a mechanically decoupled ligator device that utilizes more precise movement of the ligator head to increase the accuracy of placement of ligation rings.